MANUFACTURE OF LIGHT GUIDE ELEMENT SUBSTRATE

摘要

PURPOSE:To obtain a high-efficiency light guide element with performs low-voltage operation and has small light propagation loss and superior practicability by making the part constituting an operating element higher in substrate temperature than any other part and vapor-depositing a thin-film waveguide substrate so that the content of lead is small. CONSTITUTION:A sapphire substrate 21 is fixed contacting a heat substrate holder 22 at some part 23. The contacting part 23 is vapor-deposited with this arrangement while held higher in temperature than the other part 24. A waveguide pattern 31 is so formed that the area 23 is an operating function part. Namely, the pattern 31 is formed by etching the whole of the thin film 22 except the pattern 31 into a projecting waveguide structure, and aluminum electrodes 32 and 32' are added to form a total reflection type waveguide switch element. This switch polarizes light traveling from l1 to l3 to l2 by applying a voltage between the electrodes 32 and 32', so its operating voltage is extremely small and the propagation loss is <=1dB/cm to a 633nm wavelength, obtaining superior characteristics.